Engine designers are continually striving for more efficient engines that provide a better value to customers and last for a longer time period. As such, engine designs are becoming more severe and the need for improved deposit control is on the forefront.
In addition to cleanliness, marine diesel engines have requirements for superior demulsibility to shed water from the lubricant. This allows the oil and the equipment to last longer by preventing poor lubricity, corrosion, and rust.
In particular, large 2-stroke marine diesel engines include an engine, a crankcase, and a propeller. Marine system oils are commonly used to lubricate the crankcase of marine engines. Marine system oils tend to lose certain performance characteristics and benefits over time in marine environments. Marine system oils are particularly susceptible to performance deterioration due to the introduction of water into the marine drivetrain. Normally water separates from oil, and in an engine or drivetrain, should this not occur, the water will induce corrosion and lead to the hydrolysis of certain lubricant additives leading to acidic byproducts that attack the engine or drivetrain further.
Current system oils provide Komatsu Hot Tube deposit results (from 10=best to 0=worst) in the range of 5.5 down to 1.5 at 285° C. and 1.5 down to 0 at 300° C. Improved deposit control can be achieved by increasing the treat rate of detergent additives, but typically at the cost of demulsibility performance. Current technologies cause demulsibility problems when the detergent additive treat rate is increased.
A major challenge in engine oil formulation is simultaneously achieving improved deposit control, while also achieving maintained or improved demulsibility performance.
Despite the advances in lubricant oil formulation technology, there exists a need for an engine oil lubricant that effectively improves deposit control, while also achieving improved demulsibility performance.